Apodized Diffractive IOL for Intermediate Vision
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Solution Overview
Problem
Current diffractive intraocular lenses (IOLs) provide limited intermediate vision quality while maintaining far and near vision, with a need for enhanced intermediate image quality without degrading far and near vision capabilities.
Innovation Solution
A diffractive IOL design featuring a diffractive structure with zone boundaries that create a sufficient phase delay difference to direct a portion of incident light to an intermediate location between near and far foci, utilizing a combination of phase delay differences, apodized step heights, and aspheric surface profiles to optimize intermediate vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional diffractive IOL designs are used to provide far and near foci, then far and near vision are maintained, but intermediate vision quality is limited
Solution Approach 1:
The diffractive structure is divided into multiple zones (first diffractive zone, second diffractive zone, etc.) with different phase delay characteristics. Each zone is separated by zone boundaries that impart different optical phase delays, allowing independent control of light distribution to achieve intermediate vision while preserving far and near vision.
Solution Approach 2:
Different regions of the lens are assigned different functional properties through the zone structure. The first diffractive zone provides one set of optical characteristics while the second diffractive zone provides different characteristics, creating local variations in optical quality to simultaneously optimize intermediate, far, and near vision.
2Adaptability or versatility
If zone boundaries are configured to direct light to intermediate location, then intermediate vision is enhanced, but phase delay precision requirements increase
Solution Approach 1:
The invention specifies that the difference in optical phase delays between consecutive zone boundaries should be greater than about 1/20 wavelength (preferably greater than about 1/4 wavelength). This parameter threshold provides a clear manufacturing target that balances intermediate vision enhancement with achievable manufacturing precision.
3Adaptability or versatility
If apodized step heights are used in zone boundaries, then light distribution is optimized, but manufacturing complexity increases
Solution Approach 1:
The step heights of zone boundaries are made non-uniform (apodized), with different heights at different radial positions. This creates local variations in phase delay that optimize light distribution for intermediate vision while maintaining the overall diffractive structure's functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances intermediate vision quality by directing light to an intermediate focus between near and far foci, improving image clarity while maintaining effective far and near vision capabilities, with adjustable phase delays and surface curvatures tailored to specific optical powers and wavelengths.
Implementation Method 1
A diffractive structure comprising a plurality of diffractive zones is disposed on at least one of those surfaces so as to provide a near focus. Each zone is separated from an adjacent zone by a zone boundary that imparts an optical phase delay to the incident light.
Implementation Method 2
at least two consecutive zone boundaries (two zone boundaries separating one common diffraction zone from two different zones) are configured such that a difference between their associated phase delays for at least one wavelength of the incident light is greater than about 1/20 wavelength (λ)
Data Source
Figure 1A~1B
Figure 2~3A
Figure 3B~4B
AI summary
In one aspect, the present invention provides a diffractive ophthalmic lens (e.g., a diffractive IOL) that includes an optic having an anterior surface and a posterior surface, where the optic provides a far focus. A frustrated diffractive structure comprising a plurality of diffractive zones is disposed on at least one of those surfaces so as to provide a near focus. Each zone is separated from an adjacent zone by a zone boundary that imparts an optical delay to the incident light. Further, at least two consecutive zone boundaries arc configured such that a difference between their associated phase delays for at least one wavelength of the incident light is greater than about ¼ wavelength so as to direct a portion of the incident light to a location between the near and far foci.